docs/UI_DESIGN.md

@@ -97,14 +97,16 @@ dismisses as soon as the lobby is ready. The pure layout and timing live in `lib
   which leaks into the Telegram Desktop webview and otherwise fights it) and the Settings
   theme switcher is hidden; the nav bar takes Telegram's background and `setHeaderColor` /
   `setBackgroundColor` / `setBottomBarColor` paint Telegram's own chrome to match; the
-  native header **BackButton** drives back-navigation (the app's chevron is hidden in
+  app's **own back chevron** (Header) drives back-navigation on every platform — the native
-  Telegram); **HapticFeedback** fires on tile placement / commit / error; on **mobile**
+  Telegram BackButton is not used, as it does not render reliably in the windowed Mini App;
-  clients the app enters **immersive fullscreen** on launch (`requestFullscreen`, Bot API
+  **HapticFeedback** fires on tile placement / commit / error; the app calls `expand()` for the
-  8.0+) like Telegram's own Mini Apps, while desktop keeps the bot's full-size window;
+  bot's full-size (max-height) window but **never `requestFullscreen`** — immersive fullscreen hid
-  **closing confirmation** is enabled while a game is open **on mobile only** (on desktop
+  the native header (and its BackButton) and the Android system swipe-back then minimised the app,
-  closing is deliberate and the "changes may not be saved" dialog is just noise — move drafts
+  so it stays windowed with Telegram's thin native header (close) above the app's own header; move
-  auto-save); **vertical swipes** (swipe-to-minimise)
+  drafts auto-save, so there is **no closing-confirmation guard**; a hidden **debug panel** (ten
-  are disabled so they don't fight tile drag or the board scroll; **external links** (the word-check
+  quick taps on the header title) shows and shares a privacy-safe client diagnostic snapshot for
+  support; **vertical swipes** (swipe-to-minimise) are disabled so they don't fight tile drag or
+  the board scroll; **external links** (the word-check
   dictionary lookup, the rules link, operator-reply links) open through `Telegram.WebApp.openLink`
   so Telegram shows them in its in-app browser instead of the WebView's "open this link?"
   confirmation a plain `target=_blank` triggers; and a live stream dropped

ui/src/App.svelte

@@ -2,13 +2,13 @@
   import { onMount } from 'svelte';
   import { cubicOut } from 'svelte/easing';
   import { app, bootstrap } from './lib/app.svelte';
-  import { navigate, router, type RouteName } from './lib/router.svelte';
+  import { router, type RouteName } from './lib/router.svelte';
   import { t } from './lib/i18n/index.svelte';
-  import { insideTelegram, telegramBackButton } from './lib/telegram';
   import Toast from './components/Toast.svelte';
   import Splash from './components/Splash.svelte';
   import StaleInviteModal from './components/StaleInviteModal.svelte';
   import WelcomeRedeemModal from './components/WelcomeRedeemModal.svelte';
+  import DebugPanel from './components/DebugPanel.svelte';
   import Login from './screens/Login.svelte';
   import Lobby from './screens/Lobby.svelte';
   import NewGame from './screens/NewGame.svelte';
@@ -30,19 +30,6 @@
   // another screen is not covered.
   const routeIsLobby = $derived(router.route.name === 'lobby');
 
-  // Inside Telegram, drive its native header back button: show it on any sub-screen
-  // (everything returns to the lobby root), hide it on the lobby/login. The app's own
-  // back chevron is hidden in Telegram (Header.svelte) so only the native one shows.
-  $effect(() => {
-    if (!insideTelegram()) return;
-    const r = router.route;
-    // The chat / check sub-screens step back to their game; every other sub-screen to the lobby.
-    let target = '/';
-    if (r.name === 'gameChat' || r.name === 'gameCheck') target = `/game/${r.params.id}`;
-    else if (r.name === 'feedback') target = '/about'; // back to the Settings → Info tab
-    telegramBackButton(r.name !== 'lobby' && r.name !== 'login', () => navigate(target));
-  });
-
   // Screen transitions: the lobby is the navigation root. Entering a screen from the
   // lobby slides it in from the right (forward); returning to the lobby slides the
   // screen out to the right and reveals the lobby (back). Transitions are local, so
@@ -138,6 +125,10 @@
   <Splash />
 {/if}
 
+{#if app.debugOpen}
+  <DebugPanel />
+{/if}
+
 <style>
   .splash {
     height: 100%;

ui/src/components/DebugPanel.svelte

@@ -0,0 +1,71 @@
+<script lang="ts">
+  // Hidden on-device debug panel, opened by tapping the header title ten times (Header.svelte) and
+  // closed by tapping anywhere except the Share control. It shows a privacy-safe client diagnostic
+  // snapshot (no secrets, no initData values, no IP) and shares it through the OS share sheet (or a
+  // clipboard copy on desktop) — a support aid for reproducing client-specific issues, e.g. the
+  // Telegram Android presentation quirks. Drawn from the top, just under the app header.
+  import { app, closeDebug } from '../lib/app.svelte';
+  import { connection } from '../lib/connection.svelte';
+  import { shareText } from '../lib/share';
+  import { telegramChromeDiag } from '../lib/telegram';
+
+  const report = [
+    `app: ${__APP_VERSION__}`,
+    `locale: ${app.locale}  theme: ${app.theme}  reduceMotion: ${app.reduceMotion}`,
+    `online: ${connection.online}  streamAlive: ${app.streamAlive}`,
+    `userId: ${app.session?.userId ?? '—'}  guest: ${app.profile?.isGuest ?? '—'}`,
+    telegramChromeDiag(),
+  ].join('\n');
+
+  let label = $state('Share');
+  async function share(e: MouseEvent): Promise<void> {
+    e.stopPropagation(); // a tap on Share shares; it must not also close the panel
+    const r = await shareText(report, `Scrabble debug ${__APP_VERSION__}`);
+    if (r === 'copied') {
+      label = 'Copied';
+      setTimeout(() => (label = 'Share'), 1500);
+    }
+  }
+</script>
+
+<!-- svelte-ignore a11y_click_events_have_key_events -->
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div class="overlay" onclick={closeDebug}>
+  <button class="share" onclick={share}>{label}</button>
+  <pre class="body">{report}</pre>
+</div>
+
+<style>
+  .overlay {
+    position: fixed;
+    inset: 0;
+    z-index: 10000;
+    /* Drawn from the top; the content clears the app header (~56px + the device safe-area). */
+    padding: calc(var(--tg-safe-top, 0px) + 56px) 12px 16px;
+    background: rgba(0, 0, 0, 0.82);
+    overflow: auto;
+    display: flex;
+    flex-direction: column;
+    gap: 10px;
+    align-items: flex-start;
+  }
+  .share {
+    flex: 0 0 auto;
+    padding: 7px 16px;
+    border: 1px solid var(--accent);
+    background: var(--accent);
+    color: var(--accent-text);
+    border-radius: var(--radius-sm);
+    font-size: 0.95rem;
+  }
+  .body {
+    margin: 0;
+    width: 100%;
+    white-space: pre-wrap;
+    overflow-wrap: anywhere;
+    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+    font-size: 11px;
+    line-height: 1.45;
+    color: #d6e6ff;
+  }
+</style>

ui/src/components/Header.svelte

@@ -1,17 +1,30 @@
 <script lang="ts">
   import { navigate } from '../lib/router.svelte';
-  import { insideTelegram } from '../lib/telegram';
   import { connection } from '../lib/connection.svelte';
   import { t } from '../lib/i18n/index.svelte';
-  import { app } from '../lib/app.svelte';
+  import { app, openDebug } from '../lib/app.svelte';
   import Spinner from './Spinner.svelte';
   import AdBanner from './AdBanner.svelte';
 
   let { title, back, grow = false }: { title: string; back?: string; grow?: boolean } = $props();
 
-  // Inside Telegram the native header back button (App.svelte) is the back control, so
+  // The app always shows its own back chevron when there is a back target — on every platform, in
-  // the app's own chevron is hidden to avoid two back affordances.
+  // and out of Telegram. The native Telegram BackButton is not used: it does not render reliably in
-  const showBack = $derived(!!back && !insideTelegram());
+  // the windowed Mini App (relying on it would lose back navigation there).
+  const showBack = $derived(!!back);
+
+  // Ten quick taps on the title open the hidden debug panel (components/DebugPanel) — a support aid.
+  let titleTaps = 0;
+  let lastTitleTap = 0;
+  function onTitleTap(): void {
+    const now = Date.now();
+    titleTaps = now - lastTitleTap < 400 ? titleTaps + 1 : 1;
+    lastTitleTap = now;
+    if (titleTaps >= 10) {
+      titleTaps = 0;
+      openDebug();
+    }
+  }
 </script>
 
 <header class="nav" class:grow>
@@ -24,7 +37,9 @@
       <span class="spacer"></span>
     {/if}
     {#if connection.online}
-      <h1>{title}</h1>
+      <!-- svelte-ignore a11y_click_events_have_key_events -->
+      <!-- svelte-ignore a11y_no_noninteractive_element_interactions -->
+      <h1 onclick={onTitleTap}>{title}</h1>
     {:else}
       <h1 class="connecting"><Spinner /> <span>{t('connection.connecting')}</span></h1>
     {/if}

ui/src/game/Game.svelte

@@ -24,7 +24,7 @@
   import { getCachedGame, setCachedGame, setCachedDraft, type CachedGame } from '../lib/gamecache';
   import { patchLobbyGame } from '../lib/lobbycache';
   import { applyGameOver, applyMoveDelta, applyOpponentJoined, type DeltaResult } from '../lib/gamedelta';
-  import { telegramClosingConfirmation, telegramHaptic } from '../lib/telegram';
+  import { telegramHaptic } from '../lib/telegram';
   import {
     BLANK,
     newPlacement,
@@ -228,8 +228,6 @@
     placement = tiles.length ? placementFromHint(tiles, rack) : newPlacement(rack);
   }
   onMount(() => {
-    // Guard against an accidental swipe-close losing the open game (Telegram).
-    telegramClosingConfirmation(true);
     // Render instantly from the cache (a game opened before), then refresh in the
     // background. A cold open shows the loading state until load() resolves.
     const cached = getCachedGame(id);
@@ -579,7 +577,6 @@
       clearTimeout(draftSaveTimer);
       void gateway.draftSave(id, serializeDraft(rackIds, placement.pending)).catch(() => {});
     }
-    telegramClosingConfirmation(false);
   });
 
   function onCell(row: number, col: number) {

ui/src/lib/app.svelte.ts

@@ -25,7 +25,6 @@ import {
   telegramLaunch,
   type TelegramLaunch,
   telegramOnEvent,
-  telegramRequestFullscreen,
   telegramSetChrome,
 } from './telegram';
 import { parseStartParam } from './deeplink';
@@ -56,6 +55,9 @@ export const app = $state<{
    *  launch-error screen (screens/TelegramLaunchError) — a shareable probe for why Telegram
    *  delivered no initData (seen on some Android clients) — instead of bouncing to the landing. */
   launchError: TelegramDiag | null;
+  /** Whether the hidden on-device debug panel (components/DebugPanel) is open — toggled by tapping
+   *  the header title ten times in quick succession. A support aid; carries no secrets. */
+  debugOpen: boolean;
   /** Whether the lobby's first cold load has settled (success or error). The loading splash
    *  (components/Splash.svelte) watches it to know when to dismiss; set by screens/Lobby. */
   lobbyReady: boolean;
@@ -106,6 +108,7 @@ export const app = $state<{
   ready: false,
   bootError: false,
   launchError: null,
+  debugOpen: false,
   lobbyReady: false,
   splashDone: false,
   streamAlive: false,
@@ -197,6 +200,16 @@ export function dismissWelcomeRedeem(): void {
   app.welcomeRedeem = false;
 }
 
+/** openDebug / closeDebug toggle the hidden on-device debug panel (components/DebugPanel), opened
+ *  by tapping the header title ten times — a support aid that shows and shares client diagnostics. */
+export function openDebug(): void {
+  app.debugOpen = true;
+}
+
+export function closeDebug(): void {
+  app.debugOpen = false;
+}
+
 /**
  * seedChatUnread sets a game's unread flags from an authoritative per-viewer REST view (the lobby
  * list, a game's state, or a move result): unread is any unread entry, message whether one of them
@@ -557,10 +570,6 @@ function applyTelegramChrome(launch: TelegramLaunch): void {
   syncTelegramChrome();
   syncTelegramSafeArea();
   telegramDisableVerticalSwipes();
-  // On mobile, go immersive fullscreen like Telegram's own Mini Apps; the fullscreenChanged
-  // listener (registered at bootstrap) then re-syncs the safe-area insets. Desktop keeps the bot's
-  // full-size window. No-op on clients predating Bot API 8.0.
-  telegramRequestFullscreen();
 }
 
 /** How long to wait for the dynamically loaded Telegram Mini App SDK before giving up and showing

ui/src/lib/telegram.test.ts

@@ -5,10 +5,8 @@ import {
   loadTelegramSDK,
   telegramSdkOutcome,
   routeExternalLinkInTelegram,
-  telegramClosingConfirmation,
   telegramLaunch,
   telegramOpenExternalLink,
-  telegramRequestFullscreen,
 } from './telegram';
 
 function stubWebApp(initData: string, startParam?: string) {
@@ -48,69 +46,6 @@ describe('telegram launch detection', () => {
   });
 });
 
-// stubClient stands up a fake WebApp on the given platform with spies for the mobile-gated
-// chrome toggles, so the platform gate can be asserted without a real Telegram client.
-function stubClient(platform?: string) {
-  const enable = vi.fn();
-  const disable = vi.fn();
-  const requestFullscreen = vi.fn();
-  vi.stubGlobal('window', {
-    Telegram: {
-      WebApp: { platform, enableClosingConfirmation: enable, disableClosingConfirmation: disable, requestFullscreen },
-    },
-  });
-  return { enable, disable, requestFullscreen };
-}
-
-const mobilePlatforms = ['ios', 'android', 'android_x'];
-const desktopPlatforms = ['tdesktop', 'macos', 'web', undefined];
-
-describe('telegramClosingConfirmation', () => {
-  afterEach(() => vi.unstubAllGlobals());
-
-  it('arms the close guard on mobile clients', () => {
-    for (const p of mobilePlatforms) {
-      const { enable } = stubClient(p);
-      telegramClosingConfirmation(true);
-      expect(enable, `platform=${p}`).toHaveBeenCalledOnce();
-    }
-  });
-
-  it('skips the close guard on desktop clients (the dialog there is just noise)', () => {
-    for (const p of desktopPlatforms) {
-      const { enable } = stubClient(p);
-      telegramClosingConfirmation(true);
-      expect(enable, `platform=${p}`).not.toHaveBeenCalled();
-    }
-  });
-
-  it('always lifts the guard on leave, regardless of platform', () => {
-    const { disable } = stubClient('tdesktop');
-    telegramClosingConfirmation(false);
-    expect(disable).toHaveBeenCalledOnce();
-  });
-});
-
-describe('telegramRequestFullscreen', () => {
-  afterEach(() => vi.unstubAllGlobals());
-
-  it('goes immersive fullscreen on mobile clients', () => {
-    for (const p of mobilePlatforms) {
-      const { requestFullscreen } = stubClient(p);
-      telegramRequestFullscreen();
-      expect(requestFullscreen, `platform=${p}`).toHaveBeenCalledOnce();
-    }
-  });
-
-  it('leaves desktop clients as a standard window (the bot full-size setting fills it)', () => {
-    for (const p of desktopPlatforms) {
-      const { requestFullscreen } = stubClient(p);
-      telegramRequestFullscreen();
-      expect(requestFullscreen, `platform=${p}`).not.toHaveBeenCalled();
-    }
-  });
-});
-
 describe('telegramOpenExternalLink', () => {
   afterEach(() => vi.unstubAllGlobals());
 

ui/src/lib/telegram.ts

@@ -14,11 +14,14 @@ interface TelegramWebApp {
   themeParams?: TelegramThemeParams;
   colorScheme?: 'light' | 'dark';
   isFullscreen?: boolean;
+  isExpanded?: boolean;
+  viewportHeight?: number;
+  viewportStableHeight?: number;
+  exitFullscreen?: () => void;
   safeAreaInset?: { top: number; bottom: number; left: number; right: number };
   contentSafeAreaInset?: { top: number; bottom: number; left: number; right: number };
   ready?: () => void;
   expand?: () => void;
-  requestFullscreen?: () => void;
   openTelegramLink?: (url: string) => void;
   openLink?: (url: string) => void;
   onEvent?: (event: string, handler: () => void) => void;
@@ -26,14 +29,13 @@ interface TelegramWebApp {
   setBackgroundColor?: (color: string) => void;
   setBottomBarColor?: (color: string) => void;
   disableVerticalSwipes?: () => void;
-  enableClosingConfirmation?: () => void;
-  disableClosingConfirmation?: () => void;
   HapticFeedback?: {
     impactOccurred?: (style: string) => void;
     notificationOccurred?: (type: string) => void;
     selectionChanged?: () => void;
   };
   BackButton?: {
+    isVisible?: boolean;
     show?: () => void;
     hide?: () => void;
     onClick?: (cb: () => void) => void;
@@ -292,66 +294,6 @@ export function telegramHaptic(kind: Haptic): void {
   else h.impactOccurred?.(kind);
 }
 
-/**
- * isMobilePlatform reports whether the Mini App runs on a Telegram mobile client — iOS or
- * Android (the latter reported as 'android' by Telegram for Android and 'android_x' by
- * Telegram X). Desktop clients (tdesktop, macOS, web) report other values. Used to limit
- * mobile-only chrome such as the close guard and immersive fullscreen.
- */
-function isMobilePlatform(): boolean {
-  const p = webApp()?.platform;
-  return p === 'ios' || p === 'android' || p === 'android_x';
-}
-
-/**
- * telegramRequestFullscreen asks Telegram to open the Mini App in fullscreen (Bot API 8.0+),
- * but only on mobile clients — mirroring how Telegram's own Mini Apps go immersive on phones
- * while staying a standard window on desktop (where the bot's full-size setting already fills
- * the window). A no-op outside Telegram, on desktop, or on clients predating the method.
- */
-export function telegramRequestFullscreen(): void {
-  if (isMobilePlatform()) webApp()?.requestFullscreen?.();
-}
-
-/**
- * telegramClosingConfirmation toggles the confirmation Telegram shows when the user swipes
- * the Mini App closed — enabled during an active game so it is not lost by accident. The
- * guard is only armed on mobile clients: on desktop, closing a window is deliberate and
- * Telegram surfaces a "changes may not be saved" dialog that is just noise here (drafts
- * auto-save), so the confirmation is skipped there.
- */
-export function telegramClosingConfirmation(on: boolean): void {
-  const w = webApp();
-  if (on) {
-    if (isMobilePlatform()) w?.enableClosingConfirmation?.();
-  } else {
-    w?.disableClosingConfirmation?.();
-  }
-}
-
-let backHandler: (() => void) | null = null;
-
-/**
- * telegramBackButton shows or hides Telegram's native header back button, wiring its
- * click to onClick (replacing any previous handler). The app hides its own back chevron
- * inside Telegram so only the native control shows.
- */
-export function telegramBackButton(show: boolean, onClick?: () => void): void {
-  const b = webApp()?.BackButton;
-  if (!b) return;
-  if (backHandler) b.offClick?.(backHandler);
-  backHandler = null;
-  if (show) {
-    if (onClick) {
-      backHandler = onClick;
-      b.onClick?.(onClick);
-    }
-    b.show?.();
-  } else {
-    b.hide?.();
-  }
-}
-
 /**
  * startParamFromURL reads a startapp parameter from the page URL — a bot web_app
  * launch button carries the deep-link there rather than in initDataUnsafe.
@@ -496,6 +438,34 @@ export function collectTelegramDiag(): TelegramDiag {
   };
 }
 
+/**
+ * telegramChromeDiag returns a compact, privacy-safe readout of Telegram's viewport / chrome state
+ * (platform, version, fullscreen/expanded, viewport geometry, safe-area insets, SDK-load outcome,
+ * back-button state, UA). It feeds the hidden debug panel (components/DebugPanel), opened by tapping
+ * the header title ten times. No secrets: no initData values, no IP.
+ */
+export function telegramChromeDiag(): string {
+  const w = webApp();
+  if (!w) return 'no telegram';
+  const win = typeof window === 'undefined' ? undefined : window;
+  const scr = typeof screen === 'undefined' ? undefined : screen;
+  const vv = win?.visualViewport ?? undefined;
+  const bar = typeof document === 'undefined' ? null : (document.querySelector('.bar')?.getBoundingClientRect() ?? null);
+  const sa = w.safeAreaInset;
+  const csa = w.contentSafeAreaInset;
+  const n = (v: number | undefined): string => (v === undefined ? '—' : String(Math.round(v)));
+  return [
+    `platform: ${w.platform ?? '—'}  version: ${w.version ?? '—'}  scheme: ${w.colorScheme ?? '—'}`,
+    `isFullscreen: ${w.isFullscreen}  isExpanded: ${w.isExpanded}`,
+    `inTG: ${insideTelegram()}  sdkLoad: ${sdkLoadOutcome}  backPresent: ${!!w.BackButton}  backVisible: ${w.BackButton?.isVisible}`,
+    `innerH: ${n(win?.innerHeight)}  outerH: ${n(win?.outerHeight)}  screenH: ${n(scr?.height)}  availH: ${n(scr?.availHeight)}`,
+    `screenY: ${n(win?.screenY)}  vv.offTop: ${n(vv?.offsetTop)}  vv.h: ${n(vv?.height)}`,
+    `tgViewportH: ${n(w.viewportHeight)}  stableH: ${n(w.viewportStableHeight)}`,
+    `safeArea T/B: ${n(sa?.top)}/${n(sa?.bottom)}  contentSafe T/B: ${n(csa?.top)}/${n(csa?.bottom)}`,
+    `appHeader top/h: ${bar ? Math.round(bar.top) : '—'}/${bar ? Math.round(bar.height) : '—'}`,
+  ].join('\n');
+}
+
 // --- Login Widget (web sign-in for account linking) ---
 
 // The Login Widget is the web (non-Mini-App) Telegram sign-in. It is used only to